<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>小球随机</title>
</head>
<style>
        html,body{
            height: 100%;
        }
        .ball{
            width: 120px;
            height: 120px;
            border-radius: 50%;
            position: absolute;
        }
</style>
<body>
    <script src="./js/ball.js">
        
    </script>
</body>
</html>